Competitors in trick, jump, and slalom ski and wakeboard events require tow boats capable of consistent and accurate speed control. Intricate freestyle tricks,jumps, and successful completion of slalom runs require passes through a competition water course at precisely the same speed at which the events were practiced by the competitors. Some events require that a pass through a course be made at a specified speed. Such requirements are made difficult by the fact that typical watercraft Pitot tube and paddle wheel speedometers are inaccurate and measure speed over water instead of speed over land, and wind, wave, and skier loading conditions constantly vary throughout a competition pass.
Marine transportation in general suffers from the lack of accurate vessel speed control. The schedules of ocean-going vessels for which exact arrival times are required, for example, are vulnerable to the vagaries of wind, waves, and changing hull displacement due to fuel depletion.